kernfs: invoke dir_ops while holding active ref of the target node

[karo-tx-linux.git] / fs / kernfs / dir.c

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 8c63ae1bccb6daae85cbb7317c518e059f238d3f..bfbfb48f4ad81e4df4eb2d653297c2323eed28e9 100644 (file)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -654,22 +654,36 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
 {
        struct kernfs_node *parent = dir->i_private;
        struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
+       int ret;
 
        if (!kdops || !kdops->mkdir)
                return -EPERM;
 
-       return kdops->mkdir(parent, dentry->d_name.name, mode);
+       if (!kernfs_get_active(parent))
+               return -ENODEV;
+
+       ret = kdops->mkdir(parent, dentry->d_name.name, mode);
+
+       kernfs_put_active(parent);
+       return ret;
 }
 
 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
 {
        struct kernfs_node *kn  = dentry->d_fsdata;
        struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+       int ret;
 
        if (!kdops || !kdops->rmdir)
                return -EPERM;
 
-       return kdops->rmdir(kn);
+       if (!kernfs_get_active(kn))
+               return -ENODEV;
+
+       ret = kdops->rmdir(kn);
+
+       kernfs_put_active(kn);
+       return ret;
 }
 
 static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -678,11 +692,24 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
        struct kernfs_node *kn  = old_dentry->d_fsdata;
        struct kernfs_node *new_parent = new_dir->i_private;
        struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+       int ret;
 
        if (!kdops || !kdops->rename)
                return -EPERM;
 
-       return kdops->rename(kn, new_parent, new_dentry->d_name.name);
+       if (!kernfs_get_active(kn))
+               return -ENODEV;
+
+       if (!kernfs_get_active(new_parent)) {
+               kernfs_put_active(kn);
+               return -ENODEV;
+       }
+
+       ret = kdops->rename(kn, new_parent, new_dentry->d_name.name);
+
+       kernfs_put_active(new_parent);
+       kernfs_put_active(kn);
+       return ret;
 }
 
 const struct inode_operations kernfs_dir_iops = {